# -*- coding: utf-8 -*-

# Define here the models for your spider middleware
#
# See documentation in:
# https://doc.scrapy.org/en/latest/topics/spider-middleware.html

import logging
from scrapy import signals
from scrapy.exceptions import IgnoreRequest


class RealestatecommitteeSpiderMiddleware(object):
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the spider middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_spider_input(self, response, spider):
        # Called for each response that goes through the spider
        # middleware and into the spider.

        # Should return None or raise an exception.
        return None

    def process_spider_output(self, response, result, spider):
        # Called with the results returned from the Spider, after
        # it has processed the response.

        # Must return an iterable of Request, dict or Item objects.
        for i in result:
            yield i

    def process_spider_exception(self, response, exception, spider):
        # Called when a spider or process_spider_input() method
        # (from other spider middleware) raises an exception.

        # Should return either None or an iterable of Response, dict
        # or Item objects.
        pass

    def process_start_requests(self, start_requests, spider):
        # Called with the start requests of the spider, and works
        # similarly to the process_spider_output() method, except
        # that it doesn’t have a response associated.

        # Must return only requests (not items).
        for r in start_requests:
            yield r

    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)


class RealestatecommitteeDownloaderMiddleware(object):
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the downloader middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_request(self, request, spider):
        # Called for each request that goes through the downloader
        # middleware.

        # Must either:
        # - return None: continue processing this request
        # - or return a Response object
        # - or return a Request object
        # - or raise IgnoreRequest: process_exception() methods of
        #   installed downloader middleware will be called
        return None

    def process_response(self, request, response, spider):
        # Called with the response returned from the downloader.

        # Must either;
        # - return a Response object
        # - return a Request object
        # - or raise IgnoreRequest
        return response

    def process_exception(self, request, exception, spider):
        # Called when a download handler or a process_request()
        # (from other downloader middleware) raises an exception.

        # Must either:
        # - return None: continue processing this exception
        # - return a Response object: stops process_exception() chain
        # - return a Request object: stops process_exception() chain
        pass

    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)


class TestOnlyProjectMiddleware(object):
    """
    根据project来过滤request请求
    先到先得权限, 第一个进入request请求将会占领project字段
    后来的request.meta['project']若与project不同
    则会被忽略请求, 即scrapy.exceptions.IgnoreRequest
    若project一致，则会继续深度请求
    """

    @property
    def logger(self):
        logger = logging.getLogger("TestOnlyProjectMiddleware")
        return logging.LoggerAdapter(logger, {'middleware': self})

    project = u'京都豪园'

    def process_response(self, request, response, spider):
        if "project" not in request.meta.keys():
            return response
        else:
            if self.project is None:
                self.logger.debug("当前中间件占领project为空，获取占领的project为:%s" % request.meta['project'])
                self.project = request.meta['project']
                return response
            else:
                if self.project == request.meta['project']:
                    self.logger.debug("当前project通过测试中间件, project名称为:%s" % (request.meta['project']))
                    return response
                else:
                    self.logger.debug("当前占领中间件的project为:%s, 被抛弃的project为:%s" % (self.project, request.meta['project']))
                    raise IgnoreRequest
